This invention is directed to a method of forming a composite panel with a facade comprising a planar arrangement of thin discrete facers on a body of a structural backing material.
Composite concrete and other panels have been in use for a number of years but have not been entirely satisfactory. A bare concrete panel, for example, may be found lacking aesthetically or in other characteristics such as resistance to certain chemicals, durability, excessive heat gain from the sun, dirt or grime resistance, etc. Accordingly, a number of methods have been proposed to finish the front surfaces of panels in order to improve their aesthetic and architectural appearance and other properties.
For example, a number of different methods have been tried to cast in place or otherwise adhere discrete facing units or xe2x80x9cfacersxe2x80x9d on the front surfaces of panels in finished concrete structures. As is well known, different methods have been employed in holding individual facers in a desired pattern, usually in a common horizontal plane, while concrete is cast over and about their rear surfaces so as to at least partially embed them in a wall or other panel. Facers such as thin concrete units manufactured on masonry block machines may be employed in accordance with the present invention together with bricks, tiles, natural stone, concrete pavers, etc. to provide a visually pleasing appearance or to meet functional requirements.
In manufacturing composite walls, in particular, it has been a conventional practice to provide various types of forms, grids etc. in securing the facers in face-down position prior to casting concrete or other structural material thereover. However, such methods have not been wholly satisfactory. For example, downward leakage of concrete between facers may result in concrete adhering to the front faces of the latter and in substantial added expense in subsequent removal thereof. Such prior methods have also failed to achieve economic advantage due to complicated and tedious manual steps involved in assembling and removing forms, grids, etc. Obviously, grouting between facers is also required in some designs when the panel is complete.
It is a general object of the present invention to provide a simplified method for making high quality composite walls and other panels at economic advantage, which yet results in a clean aesthetically pleasing final appearance and/or improved functional surface of the facer surfaced wall or other panel.
A further object of the invention resides in a method of making a composite panel which obviates the need for grouting between facers mounted on the panel.
A still further object is to provide a simplified method which requires an absolute minimum manpower requirement and yet results in panels pleasing in appearance and/or improved functional characteristics and a high degree of structural integrity.
In fulfillment of the foregoing objects and in accordance with the present invention, a method of forming a composite wall or other panel with a planar arrangement of thin discrete facers on a sturdy structural backing material comprises the steps of providing a flat preferably horizontal casting bed which may be of either a rigid or slightly deformable material. The ability of a casting bed to deform slightly allows the arrangement of facers accurately in a common plane despite irregularities which may occur on their front surfaces. Plastic foam or other similar materials may be employed in forming such a casting bed as well as a fine particulate material such as sand. When facers with smooth flat surfaces lacking any significant irregularities are employed, a rigid or hard surface casting bed may of course be employed preferably with a heavy paper, plastic sheet or very thin plastic foam thereover.
A plurality of facers each with a chamfer, bevel, or other recess along at least a major portion of the edges or corners between its side walls, end walls and rear wall are provided and arranged with the facers on the casting bed in abutting relationship face down. Various geometric patterns may be employed but the facers are in all cases positioned in a face down attitude and in a common plane, so that the aforesaid chamfers or other recesses are adjacent each other and open rearwardly or upwardly to define narrow elongated channels at joints between contiguous facers. Certain of the channels with two adjacent opposing chamfers may take xe2x80x9cVxe2x80x9d configurations in cross-section while others with only one chamfer may take one half (xc2xd) xe2x80x9cVxe2x80x9d configurations in cross-section.
In addition to the foregoing, sealant may be placed in the elongated recesses or channels and may also take a variety of forms. For example, elongated unitary sealing members, hardenable liquids, or fine particulate materials such as sand may be used, the latter being presently preferred. A castable structural backing material such as concrete or other cementitious material is then placed or poured rearwardly of the facers and both conforms to and adheres to the rear surfaces thereof as it cures and hardens. A composite wall or other panel is thus formed and may thereafter be moved to its operative position. For example, if the panel takes the form of a tilt-up wall poured horizontally, a simple upward swinging movement through 90xc2x0 may be effected from its horizontal casting bed.
Channels provided adjacent joints may be filled with sand, for example, prior to casting concrete thereover and the sand may later be washed or blown out of the channels to provide drainage channels to prevent water accumulation behind the facers.
Generally, the facers have a rectangular configuration and the rear corners thereof are beveled or chamfered at edges or corners between each end wall and rear wall and at least one side wall and rear wall. Chamfers or other recesses may take various configurations viewed in cross-section including rectangular and arcuate, but a flat angularly inclined surface extending between adjacent right angularly related side or end and rear facer surfaces is preferred. When a sealant such as sand is employed, a subsidiary method step may take the form of depositing sand on the rear surfaces of the facers and sweeping the same into the sealant channels with the remainder of the facer rear surfaces being cleaned for good adhesion of the concrete.
Preferably, the rear surfaces of the facers are also provided with integral rearwardly and upwardly projecting structural connecting means which are enveloped during the pouring of concrete and thereafter firmly embedded in the cured concrete for enhanced structural integrity of the wall or other panel. Such walls or other panels are found to be substantially stronger than walls or panels without facers and may even approach the strength of monolithic concrete walls or panels of equal overall thickness. The connecting means presently take the preferred form of a series of spaced apart rearwardly projecting parallel ribs integral with the bodies of the facers. Further, the ribs are preferably formed as shown in the drawings with dove-tail configurations in cross-section defining complementary generally dove-tail grooves therebetween.
Still further in accordance with the preferred form of the invention, a plurality of spring clips are provided to interconnect the aforementioned ribs. Some of the clips may be installed in interconnecting relationship on aligned ribs of contiguous facers arranged in end-to-end relationship and others on contiguous half ribs arranged in side-by-side relationship on adjacent facers in like relationship. The clips are preferably of generally dove-tail configuration viewed in cross-section with short opposing side legs defining entry openings for the dove-tailed ribs. Further, the legs of each clip are inwardly inclined toward the mouth of the clip opening so that the clips may be snapped into firm embracing engagement on the ribs in relative movement toward the ribs. Thereafter the clips serve to urge facers and especially the side-by-side facers firmly together in abutting engagement to prevent concrete leakage downwardly there-between.
Further, the clips also help to maintain the facers in a common plane preventing accidental or unintended displacement of individual facers. Still further, the clips aid in urging facers having uneven front surfaces and facers improperly positioned toward a common plane.
A tool of appropriate design may also be provided for ease of convenience in the assembly of the clips on the ribs.
Finally, a plurality of upstanding anchors may be provided with base portions mounted on the ribs of the facers and supports for horizontal reinforcing members such as xe2x80x9cre-barsxe2x80x9d may also be provided with the latter also mounted on rear surfaces of the facers in engagement with ribs and inter-rib grooves.